leucism

noun

leu·​cism ˈlü-ˌsi-zəm 

: an abnormal condition of reduced pigmentation affecting various animals (such as birds, mammals, and reptiles) that is marked by overall pale color or patches of reduced coloring and is caused by a genetic mutation which inhibits melanin and other pigments from being deposited in feathers, hair, or skin

leucistic

lü-ˈsi-stik 

adjective

Examples of leucism in a Sentence

Recent Examples on the Web

According to the National Park Service, albinism is a genetic mutation that prevents the production of melanin (a pigment that gives an animal its color) in the cells, while leucism is the partial loss of all types of pigmentation, resulting in patches of white coloration. —Charlotte Phillipp, PEOPLE, 3 Nov. 2025

However, leucism — a separate condition — can also produce white coloration in whales, according to LiveScience, meaning not all whales with an ivory complexion are true albinos. —Brendan Rascius, Miami Herald, 30 June 2025

The unusual robin, seen in Riverview Park, has partial leucism, a phrase that’s sometimes used interchangeably with piebaldism, according to the Cornell Lab of Ornithology. —Sarah Kuta, Smithsonian Magazine, 15 May 2025

The orca's pale complexion may be due to leucism or Chediak-Higashi Syndrome. —Fernando Cervantes Jr., USA TODAY, 5 Dec. 2024

Word History

Etymology

borrowed from German Leucismus, from Greek leukós "clear, white" + German -ismus -ism — more at light entry 1

First Known Use

1878, in the meaning defined above

Rhymes for leucism

• ism
• pisum
• prism
• schism
• abolitionism
• aldosteronism
• americanism
• anticommunism
• antisemitism
• antiterrorism
• bioterrorism
• colloquialism